Public views on the use of cannabis in the United States and internationally are undergoing a profound shift that coincides with emerging evidence of its use in the treatment of selected health conditions, including HIV/AIDS. Medical marijuana is increasingly the focus of legislation in states in the U.S., and decriminalization an legalization of recreational use of cannabis in selected jurisdictions has occurred recently. Within this changing public sphere and clinical environment, it is important to understand the multiple influences on cannabis use among young persons living with HIV/AIDS. Given the high rates of daily cannabis use among young men who have sex with men living with HIV/AIDS (YMSMLHIV), it is particularly important to better understand the diverse range of motives among this population. This mixed methods study will investigate the range of motives (recreational, therapeutic or medical, and stress-related) associated with heavy cannabis use among YMSMLHIV in Chicago and Denver. Our ecological approach will assess individual motives, as well as interpersonal and environmental correlates, of cannabis use among this population. This will allow for a deeper understanding of the role of cannabis in the lives of YMSMLHIV, its associations with stages of the HIV care continuum (e.g., engagement in care, ART adherence, retention in care), and identify opportunities for intervention and risk reduction. Phase 1 will consist of 30 semi- structured interviews with a sample of YMSMLHIV to investigate motives for cannabis use, including but not limited to a range of therapeutic uses, recreational uses, and stress alleviation motives. In Phase 2, we will administer a survey to 100 YMSMLHIV and a matched sample of 100 HIV-negative young men who have sex with men to investigate distribution of cannabis motives in these groups, analyze multi-level factors associated with daily cannabis use, and estimate effects of multi-level factors and cannabis use on key indicators of the HIV care continuum among the YMSMLHIV sub-sample. Our study will help delineate how prescribed and recreational use of cannabis among YMSMLHIV to alleviate stressors may differ in terms of motive, context, and setting, and identify intervention and risk reduction opportunities for this population. Ours study sites span a diverse range of environments regarding cannabis legislation, and data derived will help disentangle motives for recreational, therapeutic and medicinal use among YMSMLHIV.